Causes, incidence, and risk factors
Primary brain tumors include any tumor that starts in the brain. Primary brain tumors can arise from the brain cells, the membranes around the brain (meninges), nerves, or glands.
Tumors can directly destroy brain cells. They can also damage cells by producing inflammation, placing pressure on other parts of the brain, and increasing pressure within the skull.
The cause of primary brain tumors is unknown. There are many possible risk factors that could play a role.
- Radiation therapy to the brain, used to treat brain cancers, increases the risk for brain tumors up to 20 or 30 years afterwards.
- Exposure to radiation at work or to power lines, as well as head injuries, smoking, and hormone replacement therapy have NOT yet been shown to be factors.
- The risk of using cell phones is hotly debated. However, most recent studies have found that cell phones, cordless phones, and wireless devices are safe and do not increase the risk.
- Some inherited conditions increase the risk of brain tumors, including neurofibromatosis, Von Hippel-Lindau syndrome, Li-Fraumeni syndrome, and Turcot syndrome.
SPECIFIC TUMOR TYPES
Brain tumors are classified depending on the exact site of the tumor, the type of tissue involved, whether they are noncancerous (benign) or cancerous (malignant), and other factors. Sometimes, tumors that start out being less invasive can become more invasive.
Tumors may occur at any age, but many types of tumors are most common in a certain age group. In adults, gliomas and meningiomas are most common.
Gliomas come from glial cells such as astrocytes, oligodendrocytes, and ependymal cells. The gliomas are divided into three types:
Astrocytic tumors include astrocytomas (less malignant), anaplastic astrocytomas, and glioblastomas (most malignant).
Oligodendroglial tumors also can vary from less malignant to very malignant. Some primary brain tumors are made up of both astrocytic and oligodendrocytic tumors. These are called mixed gliomas.
Glioblastomas are the most aggressive type of primary brain tumor.
Meningiomas are another type of brain tumor. These tumors:
- Occur most commonly between the ages of 40 – 70
- Are much more common in women
- Are usually (90% of the time) benign, but still may cause devastating complications and death due to their size or location. Some are cancerous and aggressive.
Other primary brain tumors in adults are rare. These include:
- Pituitary tumors
- Primary lymphoma of the brain
- Pineal gland tumors
- Primary germ cell tumors of the brain
Signs and tests
Most brain tumors increase pressure within the skull and compress brain tissue because of their size and weight.
The following tests may confirm the presence of a brain tumor and identify its location:
- CT scan of the head
- Examination of tissue removed from the tumor during surgery or CT-guided biopsy (may confirm the exact type of tumor)
- Examination of the cerebral spinal fluid (CSF) (may reveal cancerous cells)
- MRI of the head
Brain herniation (often fatal)
- Uncal herniation
- Foramen magnum herniation
- Loss of ability to interact or function
- Permanent, worsening, and severe loss of brain function
- Return of tumor growth
- Side effects of medications, including chemotherapy
- Side effects of radiation treatments
Calling your health care provider
Call your health care provider if you develop any new, persistent headaches or other symptoms of a brain tumor.
Call your provider or go to the emergency room if you start having seizures,or suddenly develop stupor (reduced alertness), vision changes, or speech changes.
A doctor can often identify signs and symptoms that are specific to the tumor location. Some tumors may not cause symptoms until they are very large. Then they can lead to a rapid decline in the person’s health. Other tumors have symptoms that develop slowly.
The specific symptoms depend on the tumor’s size, location, how far it has spread, and related swelling. The most common symptoms are:
- Seizures (especially in older adults)
- Weakness in one part of the body
- Changes in the person’s mental functions
Headaches caused by brain tumors may:
- Be worse when the person wakes up in the morning, and clear up in a few hours
- Occur during sleep
- Be accompanied by vomiting, confusion, double vision, weakness, or numbness
- Get worse with coughing or exercise, or with a change in body position
Other symptoms may include:
- Change in alertness (including sleepiness, unconsciousness, and coma)
- Changes in hearing
- Changes in taste or smell
- Changes that affect touch and the ability to feel pain, pressure, different temperatures, or other stimuli
- Confusion or memory loss
- Difficulty Swallowing
- Difficulty writing or reading
- Dizziness or abnormal sensation of movement (vertigo)
- Eye abnormalities
- Eyelid drooping
- Pupils different sizes
- Uncontrollable movements
- Hand tremor
- Lack of control over the bladder or bowels
- Loss of balance
- Loss of coordination
- Muscle weakness in the face, arm, or leg (usually on just one side)
- Numbness or tingling on one side of the body
- Personality, mood, behavioral, or emotional changes
- Problems with eyesight, including decreased vision, double vision, or total loss of vision
- Trouble speaking or understanding others who are speaking
- Trouble walking
Other symptoms that may occur with a pituitary tumor:
- Abnormal nipple discharge
- Absent menstruation (periods)
- Breast development in men
- Enlarged hands, feet
- Excessive body hair
- Facial changes
- Low blood pressure
- Sensitivity to heat or cold
Treatment can involve surgery, radiation therapy, and chemotherapy. Brain tumors are best treated by a team involving a neurosurgeon, radiation oncologist, oncologist, or neuro-oncologist, and other health care providers, such as neurologists and social workers.
Early treatment often improves the chance of a good outcome. Treatment, however, depends on the size and type of tumor and the general health of the patient. The goals of treatment may be to cure the tumor, relieve symptoms, and improve brain function or the person’s comfort.
Surgery is often necessary for most primary brain tumors. Some tumors may be completely removed. Those that are deep inside the brain or that enter brain tissue may be debulked instead of entirely removed. Debulking is a procedure to reduce the tumor’s size.
Tumors can be difficult to remove completely by surgery alone, because the tumor invades surrounding brain tissue much like roots from a plant spread through soil. When the tumor cannot be removed, surgery may still help reduce pressure and relieve symptoms.
Radiation therapy is used for certain tumors.
Chemotherapy may be used along with surgery or radiation treatment.
Other medications used to treat primary brain tumors in children may include:
- Corticosteroids, such as dexamethasone to reduce brain swelling
- Osmotic diuretics, such as urea or mannitol to reduce brain swelling and pressure
- Anticonvulsants, such as evetiracetam (Keppra) to reduce seizures
- Pain medications
- Antacids or histamine blockers to control stressulcers
Comfort measures, safety measures, physical therapy, and occupational therapy may be needed to improve quality of life. The patient may need counseling, support groups, and similar measures to help cope with the disorder.
Patients may also consider enrolling in a clinical trial after talking with their treatment team.
Legal advice may be helpful in creating advanced directives such as a power of attorney